後方散乱光時間分解計測による散乱係数推定法の実験的検証

摘要

後方散乱光を用いた生体断層イメージングの高精度化をめざし，これまで1入射2出射系での波形演算による散乱係数推定法を考案し，シミュレーションによりその妥当性を検証してきた．今回，実験的検討により，提案手法の妥当性の検証およびその特性解析を行った．まず均一散乱媒質において，既存手法との比較を行い，同等精度の散乱係数推定が可能なことを確認した．次に，提案手法の生体への応用を念頭に，吸収係数分布不均一性の影響を調べた．散乱係数推定式から推定誤差の項を分離し，吸収不均一性パラメータとの関係を明らかにした．さらに，提案手法は既存手法よりも吸収係数分布不均一性の影響を受けにくく，実用性が高いことを確認した．%We developed a technique to estimate the reduced scattering coefficient (μ_s') of turbid medium by the time-resolved measurement of backscattered light, and verified its feasibility in simulation. Here, we examined the accuracy and the characteristics of the proposed technique in experiments. The estimated values agreed well with those measured by a conventional technique and with those reported by references. The effect of absorption inhomogeneity on μ_s' estimation was investigated. The term that represents the estimation error was successfully separated in the equation of μ_s' estimation. In an experimental analysis, it was confirmed that the proposed technique is less affected by the μ_a-inhomogeneity and more practical than conventional techniques.